352399domain: NPropertiesPrimalityPrimeyesAppears in sequencesNumerator of Sum_{k=1..n} phi(k)/k^2.at n=7A072156Class 9- primes.at n=15A081428Primes p such that p, p+4, p+10, p+22, p+24, p+42 are all primes.at n=28A144594Prime numbersat n=30166